Rice-potato with straw mulch in winter is an economical and high-yield paddy-upland rotation system in southern China, and its effects on soil metabolites in rhizosphere may be the key to achieve the rice yield potential but it is still unclear. Based on a long-term experiment of paddy-upland rotation (since 2003 Fuyang of Zhejiang), the rice-fallow (CK) was set as control and composition and possible function of soil rhizosphere metabolites of rice-potato (straw mulch and return, RP) were evaluated. The rhizosphere soil samples were collected at full heading stage using “root bags” and evaluated by Liquid Chromatography-Mass Spectrometry (LC-MS). The results show that: 1) By using the OPLS-DA model, 201 different expressed rhizosphere soil metabolites (VIP >1 and P<0.05) are screened out under the RP rotation, as compared to that under CK, and these metabolites are attributed to 11 super-class, such as lipids and lipid-like molecules, organic acids and derivatives, organic oxygen compounds, etc. (based on HMDB database). In addition, the abundances of phenylpropanoids and polyketides, prenol lipids, benzene and substituted derivatives, steroid lactones, amino acids/peptides, carbohydrates and fatty acyl glycosides are changed significantly in response to the change of rotation from CK to RP, which indicate that these metabolites could be used as characteristics traits of rhizosphere soil metabolites of rice to distinguish the RP rotation from CK. 2) Organic oxygen compounds, organic acids and derivatives, phenylpropanoids and polyketides have significant positive correlation with the differences of soil organic matter, total potassium, available nitrogen and available potassium (r=0.816-0.938), which not only provide the nutrient matter directly or indirectly, but also assist in promoting the rice growth. 3) Phenylpropanoids and polyketides, nucleosides/nucleotides and analogues, lipids and lipid-like molecules, which have significant positive correlation with rice grain yield (r= 0.957-0.999), might improve the stress resistance of rice by participating in a series of metabolic pathways.