Abstract: Citrus maxima cv. ‘Dongshizao’ was selected as the experimental material to evaluate the effects of different droughtresistant measures on its physiological characteristics during the key phenological phases. Four droughtresistant measures （black plastic， white plastic， weeds and water retention agent） with a control treatment were carried out in field. The results showed that soil moisture content （SMC） was increased in the treatments of mulching with black plastic， white plastic and weeds or adding water retention agent. The content of soluble protein （SP）， proline （Pro）， soluble sugar （SS） and sucrose （Suc） in pomelo leaves all changed in different extents. Malondialdehyde （MDA） content and relative conductivity （REC） in all treatments were lower than that of the control， and especially for black plastic， white plastic and weed mulch， MDA and REC showed the lowest values. During the different phenological phases of pomelo， the SP of white plastic and control treatment were the highest in mature period （September）， the SP， SS， Suc， Pro and REC of other treatments had the highest values in budding period （January）， and the SP， SS， Suc and Pro of all treatments had relatively high values when pomelo was close to mature period， while they had very low values during other phenological periods. This suggested that pomelo started the corresponding resistance to stress to maintain metabolic balance by adjusting the content of osmotic regulation substances. Membership function of fuzzy mathematics method was used for comprehensive evaluation of different soil conservation measures. Using the mean value of each index membership degree in each treatment as the comprehensive appraisal standard， the effects of all the soil moisture conservation measures from high to low in order were showed as: black plastic mulch>weeds coverage>white plastic mulch>water retention agent>control.

Key words: Citrus maxima, coverage, water retention, soil moisture content, physiological characters, comprehensive evaluation