The invention discloses a photovoltaic power supply power prediction method based on positive and negative error variable weights. The method specifically includes the following implementation steps that firstly, n optical power prediction models are set, N prediction time points exist, and y(t) is a true value of photovoltaic power generation power at the tth moment; then, a prediction result is subtracted with the true value, and the weight of the tth moment of the ith model is calculated; finally, a final prediction result is obtained through n prediction values. The method solves the problems that prediction precision of a prediction method in the prior art can not meet requirements, and the prediction effect is poor.