Abstract: In order to reduce tuber quality reduction and tuber loss during storage, and provide a theoretical basis for the rational application of calcium（Ca） fertilizer to potato, the trial was conducted with the early-maturing variety ’Youjin’ as the test material and field trials were conducted from 2021 to2022 in Beilin District, Suihua City, Heilongjiang Province. Five treatments were set up with CaO dosages of 0（CK）, 20（Ca20）, 40（Ca40）, 60（Ca60） and 80（Ca80） kg·hm^-2, the tuber yield and tuber quality before and after storage were measured for each treatment, and the storage resistance of each treatment was evaluated. The results showed that the two-year commercial potato rate increased by3.51%-4.81%（P＜0.05） and the average potato weight increased by 21.14%-26.98%（P＜0.05） when the CaO dosage was 40-60 kg·hm^-2compared to the CK treatment. After 90 days of storage, Ca60treatment reduced moisture loss rate, weight loss rate, weight decay rate and quantity decay rate by19.57%, 50.32%, 95.66% and 83.71%, compared to CK treatment tubers（P＜0.05）, respectively.Compared to the CK treatment, the tuber starch, vitamin C（VC） and soluble protein contents were significantly higher, and the tuber reducing sugar, nitrate and malondialdehyde（MDA） contents were significantly lower before and after storage in the Ca60 treatment, and significantly delayed the decline in tuber quality during storage（P＜0.05）. Potato tuber hardness and skin thickness increased after calcium application, and Ca60 treatment increased tuber hardness by 7.66%-16.91%（P＜0.05） and skin thickness by 47.55%-72.27%（P＜0.05）, compared to CK treatment. Combining the effects of calcium on potato tuber yield, quality and storability, the recommended application rate of CaO was 38-42 kg·hm^-2if yield was the main objective, and 50-70 kg·hm^-2if improving tuber quality and storability was the main objective.