Solid phosphoric acid catalysts have been industrially used for propene oligomerization to improve the gasoline quality. However, solid phosphoric add catalysts will lose their mechanical strength in the presence of water which is used to hydrolyze silicon phosphates to produce free phosphoric adds for maintaining the catalytic activity. In this case, to harmonize the catalyst lifetime and activity of solid phosphoric add catalysts, the properties of silicon phosphate were investigated to achieve the maximum catalytic performance. A solid phosphoric add catalyst was prepared with kieselguhr and concentrated phosphoric add. Trace water was used to promote the release of active components from silicon phosphates during the reaction. Free phosphoric acid content, as a vital property of a solid phosphoric acid catalyst, was measured by ammonia temperature-programmed desorption. The crystal phase composition of silicon phosphates in a solid phosphoric acid catalyst was analyzed by X-ray diffraction. The catalytic performance was evaluated in a fixed bed under the conditions of 210 degrees C and 4 MPa. A solid phosphoric acid catalyst with relative content of 51% Si5O(PO4)(6) and 49% SiP2O7 showed the best performance in improving catalytic activity and lifetime, and the conversion of propene was above 99% for nearly 70 h. (C) 2014 Elsevier B.V. All rights reserved.