Deblurring with water/fat separation plays a critical role in spiral imaging. The reconstruction quality depends on good off-resonant frequency estimation. A field map before each spiral imaging exam is often acquired to approximate the B0 of the scanned subject. However, the estimation errors occur due to nonconcurrent collection of the imaging data. The proposed work introduces an iterative method to update the field map based on the acquired images to improve spiral image reconstruction. The results have shown that the blurring can be reduced along with improved fat/water separation after updating the reference B0 used for reconstruction.