Based on the theory and method of spatial panel data model(SPDM), this paper makes an empirical test on the convergence of economic growth of 12 provinces in western China, by two dimensions of economic output and resident income under three stages respectively, 1978—2013, 1978—1992 and 1992—2013. The results show that for output, per capita output at different stages has no absolute β convergence; for resident income, the regional disparity of urban residents’ income is more divergent than that of rural residents. In the period of from 1992 to 2013, no matter output per capita or income per capita is significantly divergent, and the economic disparity tends large. The economic output and resident income have significant spacial demonstration effect and spacial transferring effect, which means regional economic development and exogenous shock have significant effect on adjacent areas. When the overall western economic development is promoted in the new round and the gap between the East and the West is narrowed, the gap among provinces in the West also should be narrowed. The acceleration of urbanization process and the promotion of regional economic cooperation is helpful to bridge the gap among provinces in the West.