1. A speech recognition method, comprising: receiving, by a speech recognition device, an input speech, wherein the speech recognition device comprises a noise type detection engine, a storage area and a speech engine; dividing the input speech, by the speech recognition device, into detection speech at a beginning of the input speech and a to-be-recognized speech following the detection speech, wherein a length of speech data comprised in the detection speech is less than a length of speech data comprised in the to-be-recognized speech; selecting, by the noise type detection engine based on comparing the detection speech with a plurality of speech training samples under a plurality of different sample environments, a sample environment corresponding to a speech training sample among the plurality of speech training samples that has a minimum difference with the detection speech, as a detection environment type, wherein the plurality of sample environments comprises a quiet environment and a noise environment; detecting, by the speech recognition device, a storage area; outputting, by the speech recognition device, when a recognizable previous environment type exists in the storage area, a speech correction instruction according to a result of comparison between the detection environment type and the previous environment type, wherein the previous environment type comprises a quiet environment or a noise environment; controlling, by the speech engine according to the speech correction instruction, correction on the to-be-recognized speech, and outputting an initial recognition result; separately comparing, by the noise type detection engine, the received to-be-recognized speech with the plurality of the speech training samples, and selecting a sample environment corresponding to a speech training sample among the plurality of speech training samples that has a minimum difference with the to-be-recognized speech, as a current environment type; storing, by the speech recognition device, the current environment type to the storage area, and abandoning the current environment type after a preset duration; and outputting, by the speech recognition device, a final recognition result after a confidence value of the initial recognition result is adjusted according to the current environment type.