Meteorological factors have an impact on the operating temperature of line, and the operating temperature of line is closely related to line impedance and fault outage rate. The influence of meteorological factors on the multiple parameters of line is not fully considered when evaluating the reliability of power systems. In this context, based on weather-dependent heat balance equation of transmission line, the calculation method of line temperature considering meteorological factors and the real-time capacity model of transmission line dependent on meteorological conditions are firstly studied. And then, the impedance parameter model and the real-time outage rate model of transmission line are established, which are dependent on the line temperature. Next, a power system operation reliability evaluation method considering meteorological factors is proposed based on Monte Carlo simulation. Finally, taking the IEEE 14-bus and IEEE RTS96-bus modified systems as examples, the influence of meteorological factors on the real time parameters of transmission lines including capacity, temperature, impedance, failure rate, and on the operation reliability indices of power systems are analyzed. Case results verify the correctness of the proposed operation reliability model of transmission line and the operation reliability evaluation method of power systems considering meteorological factors.