The invention provides a main blade and ground blade mechanical locking device of a generator bus isolating switch. The main blade and ground blade mechanical locking device of the generator bus isolating switch comprises a main blade revolving shaft and a ground blade revolving shaft on the isolating switch, the main blade revolving shaft and the ground blade revolving shaft are respectively connected with a poke rod and a locking sleeve, the poke rod on the main blade revolving shaft is connected with a main blade movable key capable of being inserted in the locking sleeve connected onto the ground blade revolving shaft through a group of connecting rod mechanisms, the poke rod on the ground blade revolving shaft is connected with a ground blade movable key capable of being inserted in the locking sleeve connected with the main blade revolving shaft through a group of connecting rod mechanisms, the group of connecting rod mechanisms are mainly composed of a transmission rod connected with the poke rods through pins and a transmission connecting rod, the front end of the transmission connecting rod is connected with the movable keys, the rear end of the transmission connecting rod is connected with an oscillating rod, the middle of the oscillating rod is fixed by a pin, and two ends of the oscillating rod are respectively connected with the transmission rod and the transmission connecting rod. The main blade and ground blade mechanical locking device of generator bus isolating switch has the advantages of being simple in structure, convenient to install, capable of improving locking reliability and the like.