With photovoltaic generation developing rapidly across the world， there are MW grade solar parks being connected directly into the power system. The impact on total transfer capability（TTC） of interconnected power systems becomes a very important issue. Taking into account of the uncertainties of solar park， a point estimate method and Cornish-Fisher expansion based probabilistic calculation of TTC containing solar park is investigated. with the point estimate method， the probabilistic problems can be handled as those corresponding to deterministic problems. The interior point method is employed to calculate TTC on the estimated points of random variables， and the statistical properties of TTC are obtained. According to Cornish-Fisher expansion， the probabilistic distribution functions are calculated. Numerical results of IEEE 30-bus test system are presented. The proposed method has a high degree of accuracy and low computational burden compared with the Monte Carlo method.