Five resids from the Middle East and China have been hydrotreated in a pilot plant, which has three fixed-bed reactors in series. Six commercial catalysts were tested. The process conditions were 12.0-16.8 MPa, 370-405 degrees C, LHSV of 0.15-1.0 h(-1) H-2/oil ratio of 400-1000 nm(3) m(-3). The feedstocks included the following Chinese resids Shengli, Xinjiang and Liaohe. Kinetic parameters of resid hydrotreating reactions were calculated in terms of pore diffusion resistance and were correlated with some special properties of oils and catalysts. This study supplies important basic data for the selection of catalysts, for the design of composite catalyst beds and for the optimization of process conditions.