A kind of modified low toxic urea-formaldehyde resin was synthesized.The urea-formaldehyde resin has the advantages of low free formaldehyde content,low initial stickiness,good water resistance,poor dissolubility in acid and good storage stability,and it has plastic properties after curing,it is fit for sand control,water plugging,sealing and so on.The effects of different factors such as the dosage of time-delay curing agent,temperature and salinity on the properties of resin as plugging agent wered examin...