Simultaneous wireless information and power transfer (SWIPT) has recently drawn significant attention, however, due to the broadcast nature of wireless channels, guaranteeing the security of SWIPT system is an important research area. In this paper, we propose and analyze a low feedback overhead and low signal processing cost scheme, that using transmit antenna selection (TAS) to enhance physical layer security, in a MISO SWIPT system. We formulate the power splitting ratio algorithm design as an optimization problem, which maximizes the secrecy rate of the valid receiver under transmit power and energy harvesting constraints. Through solving this problem, secrecy rate-energy function was derived. The results show that as the increasing of transmit number, the larger Rs-E region can be achieved.