A new method for screening and identification 420 pesticide residues in fruits and vegetables by ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) were developed. The samples were extracted with acetonitrile/acetic acid (99:1, V/V), and clean-up by SinChERS-Nano (single-step, cheap, effective, rugged, safe, nano) column, determined by UPLC-Q-TOF/MS. The accurate mass database and MS/MS database which contains 420 pesticides were established, the automatic retrieval of detection results was carried on according to the accurate mass, retention time, isotope ratio, ion fragment information, and so on. Method verification was performed on leeks samples. The results showed that 420 pesticides had good linearity in the range of 0.1–100 μg/L, and the correlation coeffificients (R²) was greater than 0.990. The limits of detections (LODs) and limits of quantifications (LOQs) of 420 pesticides were in range of 0.05–2.0 and 0.1–5.0 μg/L, respectively. The average spike recoveries at 3 levels were 70.1% to 119.7%, and the relative standard deviations (RSD) were lower than 20% (n = 6). With this method, a survey of pesticide residues was conducted for 110 samples of 10 different fruits and vegetables, which provided scientific data for ensuring pesticide residue safety of the fruits and vegetables consumed daily by the public. This method was simple, sensitive and accurate, and could be used for rapid screening of 420 pesticide residues in fruits and vegetables.