Objective To evaluate the difference of oral sodium phosphate (NaP) and polyethylene glycol-electrolyte lavage solution (PEG-ELS) in the aspects of cleansing efficacy, tolerance, and safety in clinical practice, so as to provide evidence for clinical practice. Methods A systematic review of all the relevant randomized controlled trials (RCTs) was performed according the handbook of the Cochrane Collaboration. RCTs were identified from The Cochrane Library(Issue1,2004) MEDLINE(1980-2004), EMBASE(1984-2004),and CBM(1978-2004).Handsearching was also performed .RCTs comparing the two methods were selected .Tow reviewers independently assessed the quality of included trials and extracted data independently .Results Eighteen trials involving 3668 patients were included .Sub-group analysis was performed. Nap tablet had higher rate of adequate cleansing quality (RR1.08,95%CI1.02 to 1.05,p=0.01).Two-day ,divided-dose oral Nap was superior in the rate of adequate cleansing quality (RR1.27,95%CI1.06 to 1.52,p=0.009). .The. rate of adequate cleansing quality in right colon of Nap was lower than PEG-ELS(RR0.79,95%CI 0.64 to 0.98,p=0.03).The rate of abdominal cramps (RR 0.84,95%CI 0.72 to 0.99),the rate of abdominal fullness (RR 0.48,95%CI 0.26 to 0.89),the rate of nausea (RR 0.65,95%CI 0.56 to 0.76)and the percentage of patients who didn’t finished their prescribed regimen (RR 0.23,95%CI0.14 to 0.36)in Nap group were lower (plt;0.05).Conclusions Compared with PEG-ELS,Nap is superior in cleansing efficacy , patients’ tolerance ,safety and economy . It is possible to promote the use of Nap in clinical practice in China .