Understanding the effects of aerosol on the regional climate change and environment requires long-term and high-resolution aerosol optical properties. An indirect method is employed to acquire aerosol optical depths (AODs) based on the atmospheric horizontal visibility and vapor pressure at 62 stations in South Central Hebei Plain (SCHP) from 1975 to 2016. Mann–Kendall tests are also applied to investigate the spatio-temporal variation of AODs in SCHP and their correlations with East Asian monsoon and secondary industry. Results indicate that large AOD values are concentrated in the southwest banding area centered in Shijiazhuang, Xingtai, and Handan, while low values in northeastern SCHP centered in Langfang and Cangzhou. Statistical analysis shows that the AODs significantly increased in summer and autumn over most regions of SCHP, except for some metropolises. Compared with the East Asian monsoon indexes (EAMI), the change in secondary industry output (SIO) is significantly correlated with variations of annual and seasonal mean AODs in SCHP from 1975 to 2016, with the highest correlation coefficient value at 0.63. The spatial distributions of correlations between EAMI/SIO and AODs indicate that AODs in winter are significantly correlated to the East Asian winter monsoon (EAWMI) over the eastern SCHP, while significant correlations between SIO and the mean AODs in summer, autumn, and year are all detected in the central–western SCHP. This research may help increase the accuracy of long-term aerosol prediction and improve air pollution control in the SCHP.