In order to realize precise location for microwave wideband signals with high accuracy， this paper investigates the correlative interferometer-based direction finding algorithm with uniform circular array and microwave photonic phase detector. Compared with the low operating frequency and narrow bandwidth of the electronic microwave phase measurement， a photonic microwave phase measurement using dual polarization Mach-Zehnder modulator （DPol-MZM） is presented with the benefits of high frequency band， wide bandwidth， ultralow loss and immunity to electromagnetic interferences. The output optical power is related to the phase shift which can be employed for the phase shift measurement. Owing to the accuracy monitoring， the proposed phase detector can measure the phase shift from -180°to 180°with ±2°measurement error. In addition， the cosine function has been chosen to replace the conventional correlation function to solve the phase ambiguity. Meanwhile， an appropriate search algorithm with large angle step should be selected to ensure that the direction finding algorithm can be operated in real time. Besides， the conicoid interpolation fitting has been exploited for compensation the measurement error caused by the large search step. Finally， representative simulations have been presented to demonstrate the validity of the microwave photonic phase measurement and the direction finding algorithm.