It usually causes lower limbs numbness and difficulty in maintaining balance when people use squat toilet. This study aims to see if using an ankle- assisted tool for squat toilet can reduce numbness in legs and enhance balance function. There are thirty-two young subjects participated in this study. Three conditions for each subject were involved: squat(q), squat with a 22.5° slope assistant-tool(qa) and stand(s), the center of pressure(COP) signals and the Electromyography (EMG) signals were collected simultaneously for each condition. The COP signals can be examined in two parts: medio-lateral (ML) and anterior-posterior (AP). The EMG signal were collected in four muscle groups, including two-side of tibialis anterior (TA) and rectus femori s(RF). This study uses traditional indeces of the COP signals and the EMG signals in order to compare with the results with other studies in literature. This research applies empirical mode decomposition (EMD) to decompose each part of the COP signal and the EMG signal. The appropriate frequency signals are selected to adopt for Hilbert transform (HT) and complex plane area analyses (AreaC). Further analyses of using multi-scale entropy (MSE) analysis were also conducted for determining the Complexity Index. The results showed that using assistant-tool can increase the balance ability and decrease the muscle strength in most analyses in this study. In the COP signal analyses, the mean velocity of qa decrease 22% than q and the AreaC of qa were significant lower than q (female P-value:0.05, male P-value:0,06) in AP direction. In MSE analysis, the balance function raises 6% in male but reduce 6% in female. The results were consistent in EMG signal analyses. The load of q is largest and after using assistant-tool the tibialis anterior muscle decrease to 25%~50% of percent maximal voluntary contraction (%MVC). The reasons of the difference between muscle strength and balance function were affected by gender and daily living style.