In order to breach the bottlenecks of high solid content BiOCl crystals induced crystal fragmentation and agglomeration, square bismuth oxychloride (BiOCl) crystals with high solid content, excellent dispersisty and controllable size were prepared by using polyethylene glycol monomethyl ether-b-polymethyl methacrylate N,N-dimethylaminoethyl ester (mPEG-b-PDMAEMA) as dispersant. Pearlescent printing coatings with different pearlescent effects were obtained by using the as-prepared BiOCl crystals of varied size as pearlescent pigment and self-made waterborne polyurethane (WPU) emulsion as binder. The morphology, size distribution and crystallinity of BiOCl crystals were investigated by optical microscope, particle size distribution analyzer and XRD, respectively. The air permeability, moisture permeability, water contact angle and fastness of the pearlescent printing coatings were tested. The results showed that fragment-free BiOCl crystals of regular square exhibited high crystallinity with solid content of 10 %. The pearlescent printing coating demonstrated air permeability of > 5500 g/m2?d and moisture permeability of 15～25 mm/s-1 with the water contact angle of above 130 ° and color fastness to rubbing and washing reaching 4 or above.