Background: Married female caregivers face a higher risk of informal care burden. There is no study to explore the effect of socioeconomic status (SES) among married female caregivers on informal care intensity in China. The purpose of this study is to empirically examine how the SES of married female caregivers affects the amount of informal care they provide for their parents/in-law in China.Methods: 8 waves of the China Health and Nutrition Survey were pooled, and that the selection comprised only those women whose parents/in law had a need for care and were living in the same city. Informal caregivers were divided into three categories: non-caregivers (0 hrs/week), low-intensity caregivers (less than 10 hrs/week), and high-intensity caregivers (10 hrs/week and above). Chi-square tests and one-way analysis of variance (ANOVA) were used to compare the SES of the women between non-, low-, and high-intensity caregivers. Multinomial logistic regression analysis was used to calculate relative risk ratios (RRR) for various SES variables to assess the relation of SES on the likelihood of a low- and high-intensity caregiving in the household, adjusting for age, marital status, family characteristics and wave. Results: Of the 2741 respondents, high-intensity and low-intensity caregivers account for 16.42% and 21.38% respectively. Multinomial logistic regression result shows that the likelihood of being a high-intensity caregiver versus (vs.) a non-caregiver increases as the caregiver’s education attainment increases (p<0.05), and high income is related to the likelihood of being a high-intensity caregiver, but it is only significant at 10% level. Urban females are 1.34 times more likely than their rural counterparts to provide low-intensity care vs. no care (p<0.05) and are 1.34 times more likely to provide high-intensity care vs. no care (p<0.05). Employed females are 1.27 times more likely than those non-employed to provide low-intensity care vs. no care (p<0.05).Conclusions: Differences in SES are found between high-intensity caregivers and low-intensity caregivers. Women with high educational attainment and urban Hukou are more likely to provide high-intensity informal care, and women who are employed and with urban Hukou are more likely to provide low-intensity care.