Study on the extraction and conditions of hesperidin in Pericarpium citri reticulatae under the detection of UV Absorption Spectrum.Experiment shows that hesperidin under certain conditions has a higher extraction rate and the higher purity:in the microwave irradiation,the petroleum ether-methanol-60% ethanol extraction in three steps,the third step in a 60% ethanol extract can be access to 80% of the hesperidin;UV detection under certain conditions may be to monitor and quantitative determination of hesperidin in the extract :The step-by-step,after extraction with petroleum ether and methanol and removal of interference,UV method will facilitate rapid determination of hesperidin content,the method is as:0.1% NaOH-75% ethanol is as blank and solvent,detecting under 362 nm,reference HPLC method,the results are with good accuracy;simplifying extraction process of hesperidin is as follows:extracted Pericarpium citri reticulatae three times by 95% ethanol under microwave irradiation,and then extracted the residue by 60% ethanol to get the result.