The aim of this study was to investigate the impact of a Chinese herbal decoction on the intracellular calcium (Ca2+) concentration of sperm and the expression of the cation channel 1 of sperm (CatSper1), which is a calcium-channel protein specific to sperm tail, in a murine model of asthenospermia induced with cyclophosphamide. After 34 days of intragastric administration of Chinese herb decoction to the murine model used, routine analyses of the mouse sperm were conducted, the intracellular Ca2+ concentration of the sperm tails was measured using flow cytometry, and the expression of CatSper1 protein was detected using reverse transcription‑polymerase chain reaction (RT-PCR). Sperm concentration, percentage of grade A and B sperm (i.e., sperm activity) and percentage of grade A, B and C sperm (i.e., overall sperm motility) of the model group mice (MG) were markedly lower compared to the control murine group (CG) (one-way ANOVA, P<0.05). Subsequent to treatment, sperm concentration, percentage of sperm activity and overall sperm motility of the large dose of herbal medicine group murine (LG) were markedly increased compared to MG mice (P<0.05). Intracellular Ca2+ concentration in MG mice was markedly lower compared to CG mice (P<0.05). However, following therapy, a significant increase was observed in the intracellular Ca2+ concentration in LG mice as compared to MG mice (P<0.05). In addition, the expression of CatSper1 in LG mice was significantly higher compared to MG mice (P<0.05), while no statistically significant difference was observed for the CG mice. Intraperitoneal injection of cyclophosphamide reduced sperm concentration, percentage of sperm activity and overall sperm motility, intracellular Ca2+ concentration and CatSper1 expression. Large doses of this Chinese herbal decoction increased sperm intracellular Ca2+ concentration, sperm concentration, and percentages of sperm activity and overall sperm motility by upregulating CatSper1 expression. The findings of this study have demonstrated a therapeutic effect of this decoction on asthenospermia.