Needle fixing and thread trimming device of sewing machine

The utility model provides a fixed needle thread trimming device of a sewing machine, which comprises a swing mechanism, the swing mechanism is in transmission connection with an eccentric swing mechanism through tooth meshing, a magnetic assembly coaxially rotates on the eccentric swing mechanism, a Hall assembly is arranged beside the magnetic assembly, and the eccentric swing mechanism is matched with a guide sliding assembly to drive a binary rod to move up and down in a reciprocating mode. The tail end of the binary rod is in driving connection with a needle rod frame through an adjusting eccentric shaft, and a needle plate is arranged below the needle rod frame. The required transmission ratio is achieved through a mechanical structure, then when the magnetic steel installed in the fixing ring rotates by a 720-degree needle stopping angle, an instruction is sent to the servo motor to stop rotating, and the requirement that the required needle rod frame reaches the fixed needle stopping position on the n