There is limited information on the knowledge and practice of salt-reduction in China. The purpose of this study was to describe the status of the knowledge and practice of salt-reduction among the Chinese population from a nationally representative survey stratified according to hypertension status. The association between hypertensive status and salt-reduction knowledge and practice was calculated using multivariate hierarchical logistic regression adjusting for related confounders. The study included 179,834 participants; 51.7% were women, and the mean age was 44 years. The levels of overall salt-reduction knowledge (7.9%) and practice (37.1%) were low. The percentage of the use of salt-control spoons and low-sodium salt was 10.7% and 12.2%. The aging population (≥60 years) had the lowest levels of salt-reduction knowledge (5.7%) than other age groups (P < 0.0001). People living in rural areas (OR = 0.64; 95% CI: 0.51, 0.81) had lower odds of using salt-control spoons. Females (OR = 1.23; 95% CI: 1.10, 1.36) had higher odds of using salt-control spoons. People living in rural areas (OR = 0.48; 95% CI: 0.36, 0.63) had lower odds of using low-sodium salt. Females (OR = 1.26; 95% CI: 1.13, 1.41) and people living in the southern region (OR = 1.43; 95% CI: 1.11, 1.83) had higher odds of using low-sodium salt. Our work highlights the need to promote education related to hypertension, salt-reduction knowledge and methods among the public and the need to strengthen strategies for the popularization of salt-reduction knowledge and practices among males, people living in rural areas, people living in the northern region and the aging population in China.