The invention relates to a novel mining counter-rotating main fan blade angle adjusting device. The device is provided with a blade, a mounting base, a positioning block, hoops and a screw, wherein ablade tenon is provided with a plane; the positioning block is provided with slopes with different angles and fixed to the mounting base through the screws; and the hoops are used for radically locking the blade tenon; and the two semicircular hoops are locked through the screws. The device is reasonable in structural design, the defects of tenon thread failures, rusting or non-removable engagement of tenons and tenon sleeves, difficult blade rotation and low angle adjusting precision of traditional structures can be effectively overcome, in addition, the structural design is reasonable, the effect that the blade angle is flexible and convenient to adjust and high in precision can be reliably ensured, and the safety and reliability of a mining counter-rotating main fan are greatly improved.