In this paper, we study the physical layer security in a two-tier heterogeneous wireless sensor networks (HWSN) based on simultaneous wireless information and power transfer (SWIPT) approach. Joint optimization problem of the transmit beamforming vector at the macrocell and femtocell, the artificial noise (AN) vector, and the power splitting ratio is modeled to maximize the minimal secrecy capacity of the wiretapped macrocell sensor nodes while considering the fairness among multiple M-SNs. In order to reduce the performance loss of the rank relaxation, we apply successive convex approximation (SCA) technique, first-order Taylor series expansion and sequential parametric convex approximation approach to transform the max-min program to a second order cone programming (SOCP) problem to iterate to a near-optimal solution. In addition, a novel SCA-based iterative algorithm is proposed while its convergence property is proved. The simulation shows that our SCA-based method outperforms the conventional methods.