To reveal the long-term variation patterns and regional differences of precipitation phases in Shandong Province, this study utilized daily precipitation phase product from 116 national ground-based meteorological stations in Shandong during 1970–2024. The spatiotemporal distribution characteristics of three precipitation phases (rain, snow, and mixed rain-snow) were analyzed, and the primary phases and causes of precipitation phase transitions across the province and its meteorological geographical regions were identified. The results show: (1) Pure rain exhibits a spatial pattern of higher amounts in the south and lower in the north, with annual mean pure rain amount accounting for over 96% of total precipitation. The southern Shandong region is the provincial high-value center for pure rain (amount 719.3 mm, days 71.2 d). Pure snow and mixed rain-snow are concentrated in the Shandong Peninsula, with its northern coastal area forming a "snow hollow "high-value zone (snow amount ≥20 mm, snow days ≥13 d). (2) On the interannual scale, total precipitation in Shandong Province exhibits a weak increase (14.1 mm/10a) accompanied by a decreasing trend in precipitation days (?1.6 d/10a). The Shandong Peninsula is the most sensitive region to precipitation phase changes, where winter precipitation phases show a bipolarization toward pure rain and pure snow, with snowfall intensity in the northern part significantly higher than in the south. On the monthly scale, pure rain is predominant in the summer half-year, accounting for 57.1%–63.9% of the annual total from May to September; pure snow increases in the winter, while mixed rain-snow concentrates in the winter-spring and autumn-winter transitional seasons. (3) Both snowfall ratio indices indicate that pure rain is the absolutely predominant phase in Shandong Province. The Shandong Peninsula is the only region where snowfall days exceed pure rain days during the snowfall season (snowfall day ratio: 0.5), although the proportion of pure rain continues to rise (snowfall amount tendency rate: -0.02 /10a, snowfall day tendency rate: -0.04 /10a). This study provides scientific basis for water resource management and winter sea-effect snowstorm disaster prevention in Shandong Province.