LP01 and LP11 mode interferences in high-birefringence (Hi-Bi) panda fibers are theoretically and experimentally presented. The propagation characteristics of both the fundamental and second-order modes in Hi-Bi panda fibers are investigated, and the interference output intensity distribution of the LP01 and LP11 modes in panda fibers are thoroughly examined. An experiment is conducted to verify the feasibility of modal interference sensors. The results show that the two-lobe interference pattern of panda fibers generates energy exchanges when external strain is applied on the fiber. Moreover, Hi-Bi panda fibers can be used to design voltage sensors.