Tumuji oil sand from Inner Mongolia was subjected to sub- and supercritical water extraction on a semicontinuous apparatus. The experiments were carried out to investigate the effect of temperature on extract yield, formation rate, and product components at different pressures. The results indicated that extract yield increases with the increase of pressure and a maximum extract yield of 81.1 wt % could be obtained at 30 MPa. The formation rate of extract has a maximum with the variation of temperature. With increase of pressure from 20 to 30 MPa, the maximum extract formation rate increases from 32.99 x 10(-5) to 58.37 x 10(-5) s(-1) and the temperature corresponding to the maximum extract formation rate moves from 412 to 390 degrees C. The extract was fractionated into oil, asphaltene, and preasphaltene, and the oil was further fractionated into saturates, aromatics, and resin. The results show that formation rates of saturates, aromatics, and resin all have a maximum with the variation of temperature. The temperature corresponding to the maximum formation rates of saturates and aromatics decreases, while that of resin increases with increase of pressure. The gas yield is quite low, and the main gas components are CO2, CH4, and H-2.