In this work, the drug-release behavior was achieved by controlling the hydration crystal morphology formed during the setting reaction of cement. Two kinds of calcium phosphate cement (CPC) matrix with different and typical crystal morphology were prepared, and the cumulative percentage of gentamicin sulfate (GS) released from the hydrated bone cements was characterized in vitro. The relation between the cumulative percentage and the releasing time showed that both systems exhibited a reasonable low initial GS burst (about 20% and 30% for CPC-1 and CPC-2 in about 4 days, respectively) and sustained release behavior with different drug-release rates. CPC-1 and CPC-2 showed a different drug-releasing ratio after 30 days: 40% and 80%, respectively.