Abstract: The co-thermal dissolution (CTD) properties of Shenfu coal (SC) and rice straw (RS) in 1-methylnaphthalene (1-MN) at different temperatures were studied. It is found that RS gives much higher of thermal dissolution yield (TDY), suggesting its high thermal dissolution (TD) activity. But much amount of gas is produced in the TD process of RS, resulting in the low thermal soluble yield (TSY). For the TD of SC, although the TDYs of SC are much lower than those of RS, but the differences between TDY and TSY from the TD of SC are much smaller than those from the TD of RS. CTD of SC and RS shows that there exists synergistic effect which is the function of temperature. At 320 to 340℃, the TSYs have positive synergistic effect. The experimental results are larger than corresponding calculated weighted mean values of the individual TD of SC and RS. While at all the TD temperatures studied, TDYs give negative synergistic effect. The largest enhancements in TSY of 7.9% comparing with corresponding calculated weighted mean values of the individual TD of SC and RS are obtained at 320℃. The mechanism of synergistic effect produced in CTD was discussed based on the characterization of TD soluble fractions.