The invention relates to an acceleration sensor in the field of sensors of a micro electro mechanical system (MEMS), in particular to a single-chip integrated eight-beam-arm triaxial accelerometer, and solves the problems of low sensitivity, high degree of inter-axial coupling, complicated packaging structure, inconvenience for installation test and poor high-temperature resistance of the conventional accelerometer. The single-chip integrated eight-beam-arm triaxial accelerometer comprises eight elastic beam arms, a central clamped block and mass block frames, wherein the surrounding mass block frames are respectively fixed with the central clamped block through the elastic beam arms; a lower bottom surface of the central clamped block is bonded with a glass bottom cover through an electrostatic coupling technology; twelve piezoresistors having equal resistance are symmetrically distributed at both ends of the eight elastic beam arms; and the piezoresistors are connected to respectively form three Wheatstone bridges for respectively testing three axial accelerations. The single-chip integrated eight-beam-arm triaxial accelerometer is high in sensitivity, simple in packaging structure, high in reliability, low in cost, easy to integrally process, and wide in application range.