Many climate feasibility demonstration studies of major energy projects have to involve the designed parameters of dry or wet bulb temperature, but since 2001, according to the request of the China Meteorological Administration, observation stations of Anhui begin to change the observation apparatus to humidity sensors. The new apparatus does not observe wetbulb temperature. To solve this problem about data shortage, we have designed a looping iterative scheme to compute wetbulb temperature and compared the calculated results with data from humidity table. The comparison results show that the errors less than 0.1 ℃ are within 92.84 percent, the errors less than 0.2 ℃ are within 99.80 percent. The method is reliable and is more convenient and fast comparing with the traditional method. Thus it is suitable for becoming the solution of complement wet bulb data series, the scheme meets the requirement of climate feasibility demonstration work and can be widely used in power station designing, also it can be a helpful complementarity for ground historical data checking programs.