The invention relates to a mechanical assembling mechanism which comprises a drive device and at least one material taking device. The drive device comprises a first chassis, a second chassis, a rotating disc, a first lifting disc, a second lifting disc, a motor, a first rotating shaft, a first transmission rod and a second transmission rod. The motor is in drive connection to the first rotating shaft and the rotating disc. A first guide groove and a second guide groove are developed in the outer surface of the first rotating shaft. A first connecting column is arranged at the lower end of the first transmission rod and inserted into the first guide groove. A second connecting column is arranged at the lower end of the second transmission rod and inserted into the second guide groove. The material taking device comprises a base, a rocker arm, a telescoping arm, a clamp base, a second rotating shaft and a clamp, wherein the second rotating shaft is in drive connection with the clamp base and penetrates the base, the second lifting disc is in drive connection with the rocker arm, and the first lifting disc is in drive connection with the second rotating shaft. The assembling mechanism is simple in structure, long in service life, low in fault rate, high in moving speed and high in precision, program control is easy, and the production cost is reduced.