A model for a typical parabolic trough solar thermal power generation system with Organic Rankine Cycle (PT-SEGS-ORC) was built within the transient energy simulation package TRNSYS, which is formed by integrating several submodels for the trough collector system, the single-tank thermal storage system, the auxiliary power system and the heat-electricity conversion system. With this model, the effects of several key parameters, including the interlayer pressure between the absorber tube and the glass tube (P-inter), the flow rate of high temperature oil in the absorber tube (v), solar radiation intensity (I-dn) and incidence angle (theta), on the performance of the parabolic trough collector field based on the meteorological data of Xi'an city were examined. The study shows that the heat loss of the solar collector (q(loss)) increases sharply with the increase in p(inter) at beginning and then reaches to an approximately constant value. The variation of heat collecting efficiency (eta(hc)) with v is quite similar to the variation of q(loss) with Pinter. However, I-dn and theta exhibit opposite effect on eta(hc). In addition, it is found that the optimal volume of the thermal storage system is sensitively dependent on the solar radiation intensity. The optimal volumes are 100, 150, 50, and 0 m(3) for spring equinox. summer solstice, autumnal equinox and winter solstice, respectively. (C) 2012 Elsevier Ltd. All rights reserved.