The embodiment of the invention discloses a boom crane. A rotary table is mounted at a chassis, and a winding engine is mounted at the rotary table. The head end of a boom frame is hinged to the rotary table, and a lifting hook is hung to the tail end of the boom frame. One end of a lifting oil cylinder is hinged to the rotary table, and the other end of the lifting oil cylinder is hinged to the boom frame. A winding engine driving device is provided with a motor, a shaft coupler and a speed reducer, a winding drum of a winding device is connected to the speed reducer in a transmitting manner, and a steel rope is enwound to the winding drum, an upper pulley block and a lower pulley block. A brake of a brake device tightly holds a brake wheel on a high speed shaft of the speed reducer during braking, and a motor frequency changer of a control device regulates the speed of the motor by changing the frequency. According to a motor control circuit, a contactor is connected in series between a motor protection breaker and the frequency changer, and an upper limit switch and a lower limit switch are connected to a control circuit of the contactor in series. The complete machine, the subsystem or the parts of the boom crane are improved in many aspects, and the performance of the boom crane can be improved.