Today, tower cranes are indispensable equipment in the construction high buildings. Therefore, the study and caculation about stability of structural body of tower crane are meaningful content for science as well as practical. The calculation of stability for the tower crane will be provided on the calculation of stability for the space bar structures using finite element method (software SAP2000). The article will present results about the dependence of tower crane's stability on: sidebar section, diagonal section, tower height, lift load position.