Objective By comparing the differences of surface electromyography ( sEMG) signals and dynamic stability of lower limbs during cognitive dual-task walking and motor dual-task walking under different loads, the effects of dual tasks with different types and loads on dynamic postural control in healthy adults were investigated. Methods The average electromyography (AEMG) and dynamic stability indexes of 28 subjects during cognitive dual-task walking and motor dual-task walking under different loads were collected by wireless sEMG tester and three-dimensional (3D) motion capture system. The effects of task type ( cognitive task and motor task) and task load ( simple task and difficult task ) on sEMG and dynamic stability of human lower limbs and their interactions were analyzed by two-factor repeated measures of variance. Results The AEMG of left and right biceps femoris muscles and right tibialis anterior muscle during walking with simple load were lower than those during walking with difficult load (P<0. 05), and the AEMG of left tibialis anterior muscle during simple motor dualtask walking was lower than that during difficult motor dual-task walking (P<0. 05). The AEMG of right gastrocnemius muscle during difficult cognitive dual-task walking was lower than that during difficult motor dualtask walking (P<0. 05), the AEMG during simple cognitive dual-task walking was higher than that during difficult cognitive dual-task walking (P<0. 05), and the AEMG during simple motor dual-task walking was lower than that during difficult motor dual-task walking (P< 0. 05). The margin of stability ( MoS) of simple cognitive dual-task walking was larger than that of simple motor dual-task walking (P<0. 05), the MoS of difficult cognitive dual-task walking was smaller than that of difficult motor dual-task walking (P<0. 05), and the MoS of simple motor dualtask walking was smaller than that of difficult motor dual-task walking (P<0. 05). Conclusions Dual tasks with different types and loads have interaction effects on dynamic posture control. The neuromuscular control around the ankle muscle and dynamic stability during difficult motor dual-task walking are better than those during difficult cognitive dual-task walking, and the neuromuscular control around the ankle muscle and dynamic stability during difficult motor dual-task walking are better than those during simple motor dual-task walking.