Abstract: A method for simultaneous screening of 90 pesticide residues in blueberries by ultra-high pressure liquid chromatography high resolution mass spectrometry was developed. Target residues in blueberries were extracted by an improved QuEChERS protocol. Ultra-high pressure liquid chromatography coupled to quadrupole/orbitrap high-resolution mass spectrometry was employed for screening analysis with full mass scanning trigged data dependent fragment ion acquisition in positive and negative mode. The analytes were quantified by representative matrix-matched standard curve. The results showed that the optimized ratio of PSA vs C₁₈ was 1:1 with amount of 150 mg respectively in the improved QuEChERS protocol. The limits of detection and limits of quantitation of the method were 0.1~18.7 μg/kg and 0.2~20.2 μg/kg as well. The linearities for 90 pesticides were fitted by regression calculation at the range of 0.005~0.1 mg/kg with determination coefficient R²≥0.992. With calibration of the representative matrix-matched standard curve, recoveries were calculated ranging from 50.1% to 130.9% and relative standard deviations were varied in the scope of 1.0%~14.9% at the three spiking levels of 0.01, 0.05 and 0.1 mg/kg. Five pesticides were detected in the real-life blueberry samples purchased in the market, evidencing the applicability of the developed method. The proposed approach is applicable for routine pesticide monitoring in blueberries with simple sample preparation, broad analyte coverage and powerful capability of quantification and qualification.