Abstract: The traditional double long baselines interferometer (DLBI) requires the baselines to be strictly co-prime for locating algorithm. Besides, it is sensitive to the phase error and the performance becomes seriously bad with higher fuzzy number. To solve the problems, an improved direction-finding algorithm with double baselines rotating interferometer (DBRI) was proposed. In the DBRI, two baselines were designed with arbitrary length and palstance to rotate in the opposite direction. The locating was carried out according to the phase difference gotten from the improved direction-finding algorithm, obtaining better location precision with high fuzzy number and better robust to the phase discrimination error. Finally, the effectiveness and validity of the proposed algorithm were verified by computer simulations.