Hoist single girder gantry crane ( known as single-beam gantry crane under ) structure is simple, saving timber , which has been widely used . Domestic large truss gantry crane had been dynamic load test , the United States , the former Soviet Union , Japan and other countries who were on the Trolley double girder gantry crane dynamic analysis conducted , but more emphasis on research and analysis methods , were not discussed single-beam gate motorized stiffness problem. The single-beam gantry crane has the following characteristics and problems exist : single girder gantry crane trolley simple than double girder gantry crane structure, technology is good . However, the small component size , resulting in space stiffness weak. Electric Hoist lifting speed constant , the driver can not control, and easy -on-one greater impact door beams , impact on jobs and ergonomics. Crane design specifications and door product quality grading standards are regulations have dynamic stiffness requirements, but for single girder gantry crane is still a lack of regulations. Therefore it is necessary to analyze and study the dynamic performance for single girder gantry crane , single girder gantry motor to provide stiffness calculation method recommended by the dynamic stiffness of the control value for the system orders beam gantry 15 ton Electric Chain Hoist product quality grading standards and improve the level of product design and quality to create conditions .