1. A control method for accessing a Java card object comprising: step S 1 , interpreting and executing, by a Java card virtual machine, an applet of a current application; step S 2 that includes sub-steps obtaining, by the Java card virtual machine, an object reference provided by a current execution instruction in the applet, obtaining a current accessing object from a preset storage area according to the object reference, and reading a current context value of the current accessing object; step S 3 , obtaining, by the Java card virtual machine, a type of the current accessing object according to the current execution instruction, wherein, if the type of the current accessing object is method invoking, going to step A 1 , wherein, if the type of the current accessing object is a READ/WRITE object, going to step B 1 , and wherein if the type of the current accessing object is neither the method invoking nor the READ/WRITE object, going to step C 1 ; step A 1 , determining whether the current accessing object is a shared interface method invoking object, wherein, if the current accessing object is a shared interface method invoking object, going to step A 2 , and wherein, if the current accessing object is not a shared interface method invoking object, going to step B 1 ; step A 2 , determining whether a packet to which the current accessing object belongs is an active packet based on the current context value of the current accessing object, wherein, if the packet to which the current accessing object belongs is an active packet, going to step S 4 , and wherein, if the packet to which the current accessing object belongs is not an active packet, prompting an exception; step B 1 , determining whether the current accessing object is prevented by a firewall or satisfied a basic detecting condition, wherein, if the current accessing object is not prevented by the firewall or satisfies the basic detecting condition, going to step 54 , and wherein, if the current accessing object is prevented by the firewall or does not satisfy the basic detecting condition, prompting an exception; step C 1 , determining whether the current accessing object satisfies the basic detecting condition, wherein, if the current accessing object satisfies the basic detecting condition, going to step S 4 , and wherein, if the current accessing object does not satisfy the basic detecting condition, prompting an exception; and step S 4 , executing, by the Java card virtual machine the current executing instruction, wherein the determining whether the packet to which the current accessing object belongs is an active packet based on the current context value of the current accessing object comprises: traversing, by the Java card virtual machine, all channels; comparing a packet index in the current context value of the current accessing object with values respectively stored in the channels, wherein the packet index indicates a storage address of the packet to which the current accessing object belongs; and determining whether there exists a channel storing the value which equals to the packet index, wherein the packet to which the current accessing object belongs is an active packet if there exists a channel storing the value which equals to the packet index, and wherein the packet to which the current accessing object belongs is not an active packet if there does not exist a channel storing the value which equals to the packet index.