The longitudinal and transverse, resistivities pzz and pzy, of high-T, YBa2Cu3Oy, films and (YBa2Cu3Oy/YxPr1-xBa2Cu3Oy)n superlattices in a mixed state have been measured systematically to investigate the effects of magnetic field and flux pinning on the behaviors of pxy and pxx, the subscript n refers to the number of modulation layer in superlattices. Sign reversal of Hall coefficients is observed and depends on the pinning force. The power law, pxy = Apt,, persists in (YBa2Cu3Oy/YxPr1-xBa2Cu3Oy)n superlattices with and without sign reversal.