Objective:To explore the association between serum 25-hydroxyvitamin D[25(OH)D]and handgrip strength in middle-aged and elderly people in 5 cities of Western China.Methods:Based on the data of a cross-sectional survey conducted in the 5 cities of Western China from February to July 2023,the relevant demographic characteristics of people were collected by questionnaire,handgrip strength was collected by physical examination,and serum 25(OH)D was detected by HPLC-MS/MS.The association between the serum 25(OH)D and handgrip strength was analyzed using Logistic regres-sion and Chi-square test for between-group comparisons models.Results:The prevalence of 25(OH)D deficiency and insufficiency among the middle-aged and elderly people in the 5 cities of Western China was 52.9％and 34.5％,respectively.The people who were older,female,and sampled in winter had lower serum 25(OH)D levels(P＜0.05).The prevalence of loss of handgrip strength among the mid-dle-aged and elderly people was 25.3％.The prevalence of handgrip strength loss was higher in the aged 65-80 participants with 25(OH)D deficiency(45.0％)than in those with 25(OH)D insufficiency(32.6％)and 25(OH)D sufficiency(20.6％).The highest prevalence of loss of handgrip strength was found in the aged 75-80 participants with 25(OH)D deficiency(62.1％),followed by the 25(OH)D insufficient group(11.1％,P＜0.05).The study found that middle-aged and elderly people with 25(OH)D deficiency had a 1.4-fold increased risk of handgrip strength loss compared with those with 25(OH)D sufficiency(OR=2.403,95％CI:1.202-4.804,P=0.013).No significant association was found between 25(OH)D insufficiency and handgrip strength status in the middle-aged and elderly people.For every 5 μg/L increase in total serum 25(OH)D,the risk of handgrip strength loss reduced by 13.1％(OR=0.869,95％CI:0.768-0.982,P=0.025).For every 5 μg/L increase in serum 25(OH)D2,the risk of handgrip strength loss reduced by 24.1％(OR=0.759,95％CI:0.582-0.990,P=0.042).No significant association was found between serum 25(OH)D3 levels and the risk of hand-grip strength loss.The risk of handgrip strength loss in middle-aged and elderly people was reduced by 25.2％for each incremental increase in the total serum 25(OH)D levels(deficient,insufficient and suf-ficient)(OR=0.748,95％CI:0.598-0.936,P=0.011).The risk of handgrip loss was reduced by 40.0％for each incremental increase in serum 25(OH)D levels in the aged 65-80 and aged 65-69 participants,and by 80.0％for each incremental increase in 25(OH)D levels in the aged 75-80 parti-cipants.Conclusion:Serum total 25(OH)D and 25(OH)D2 levels are associated with handgrip strength status in middle-aged and elderly people in the 5 cities of Western China.