With expect to reduce the systematic error and random error of gravity acceleration measurement by single-pendulum method, the structure of traditional single-pendulum experimental apparatus is improved in this paper. Combined with the automatic control and data processing of single-chip microcomputer, the automatic and accurate measurement of gravity acceleration is finally realized. The double-pendulum is applied to replace the single-pendulum structure, and the systematic error caused by the conical pendulum movement of the pendulum ball can be avoided benefiting from the stability of the "V" pendulum. Notably, we innovatively propose to use a splint to fix the double line, so as to ensure that the length of the two cycloids and the opening angle between them are fixed. In addition, the single-chip and electromagnet are used to control the release of the pendulum ball at the specified position, so as to reduce the error caused by the manual release of the ball in the traditional single-pendulum experimental apparatus. The results suggest that the improved experimental apparatus can effectively improve the measurement accuracy of gravity acceleration.