Abstract: The traditional wind speed uncertain model is limited in taking its coexisting randomness and fuzziness together into account. Therefore, this paper considered the probability distribution of wind speed and fuzziness of its parameters, and proposed a random fuzzy uncertain model for daily wind speed. By considering regional, seasonal and daily feature and taking measured data from NREL in America and a wind farm in northeast China as cases, random features of daily wind speed data of the same months from several years split into 96 periods and wind speed data of the same period of days at the same months from different years were extracted. It was found that, measured data in close to or more than 70% periods obeys Weibull distribution with double parameters, and data from the same periods possesses similarity, but shape parameter k and scale parameter c are of fuzziness. After data digging about fuzzy membership function characters of k and c by maximum likelihood method, limits of them were defined under a certain confidence level. Then, according to uncertain programming theory, wind speed was defined as a random fuzzy variable and chance measure distribution function for wind speed was obtained, thereby the wind speed uncertain model was established. Finally, modeling process and daily wind speed random fuzzy simulation method based on random fuzzy simulation technology and inverse transformation method were provided. 5 000 times of simulation results show that the probability when simulation data is in historical data limits of corresponding periods is more than 94.13%, proving the effectiveness of the model in simulating random fuzzy wind speed.