Stability of lifting operations is to ensure that the fundamental hoisting crane safety implementation. Only by fully understanding the experience of lifting characteristics, the characteristics of the device, directing the operation, understanding and mechanical stability requirements set up in order to develop a scientific and rational, safe and reliable, in line with the actual lifting programs to ensure the implementation of lifting operations Security. The main point of this article is knowledge: the role of lifting operations and content of stability; lifting operations instability causes and preventive measures; Stability Check mast. Lifting operations Instability Causes and Prevention Measures 1. Lifting instability: The main reason: overload, legs instability, mechanical failure, the mast eccentric too big. Instability 2. hoisting system; the main reason: multi-machine is not synchronized lifting; multi-machine lifting load lifting capacity of the uneven distribution of the different; more action, more jobs command and coordination failures, Mast System cable wind rope, anchors instability . Instability 3. The lifting device or component: The main reason: because the discontinuity is consistent with the design of lifting, stiffness of the device or component is small. Preventive measures: the slender, large-scale equipment or components using multi-point lifting cranes; equipment for thin-walled reinforcement strengthened; for steel structure, the weak parts of the grid structure or rod reinforcement or an increase in cross-section. 

palabras clave: Cranes, lifting equipment, Crane,