In order to explore reasonable prebedtime interventions to improve the sleep quality of the youth population, this experiment comprehensively investigated the effect of prebedtime footbath on the improvement of youth sleep quality. The experimental conditions of the experimental group were to take a 30-min footbath at 40°C 1 h before bedtime, to compare the experiment with the control group that did not take footbath, and to strictly control other environmental parameters that may affect sleep quality. We recorded the sleep of 16 male subjects using a subjective sleep quality questionnaire and polysomnography (PSG) and recorded their distal skin temperature (DST) and proximal skin temperature (PST) during footbath and sleep using temperature records. The skin temperature data showed that footbath before bedtime helped to increase DST and accelerate heat dissipation from the terminal skin, which in turn increased the distal–proximal skin temperature gradient (DPG), and we found that the DPG of the experimental group was higher than that of the control group for 84.8% of the time during the whole night’s sleep. Both subjective questionnaire and PSG monitoring results showed that sleep quality and sleep calmness could be effectively improved by taking a 30-min 40°C bedtime footbath 1 h before bedtime. The subjective sleep quality questionnaire score of the control group was only 84.1% of that of the experimental group. There were significant differences between the control and experimental groups in total sleep time (TST), sleep-onset latency (SOL), wake after sleep onset (WASO), and arousal index (AI) (p < 0.05). Compared to the control group, the experimental group showed a 43.4-min increase in TST, a 14.9-min decrease in SOL, a 32-min decrease in WASO, a 3.28 beats/hour decrease in AI, and a 9.0% increase in sleep efficiency by performing a prebedtime footbath. This study quantitatively describes the effect of prebedtime footbath on the improvement of sleep quality in young men and provides an effective reference for the rational improvement of sleep quality in young people.