Sustained-releasing praziquantel (SRP) tablet was designed for single dose treatment regimen of clonorchiasis. A previous pre-clinical study confirmed its sustained-releasing characteristics and a better cure rate than conventional praziquantel (PZQ). In this clinical study, the pharmacokinetics of this SRP tablet were investigated in human volunteers (phase 1; 12 volunteers), and its curative efficacy was examined in clonorchiasis patients (phase 2; 20 volunteers). In the phase 1 clinical study, blood concentrations of both tablets showed wide individual variation. The $AUC_{last}$ of SRP was $497.9{pm}519.0ng{cdot}hr/ml;(mean{pm}SD)$ and PZQ of $628.6{pm}695.5;ng{cdot}hr/ml$, and the $AUC_{inf}$ of SRP was $776.0{pm}538.5;ng{cdot}hr/ml$ and of PZQ $658.6{pm}709.9;ng{cdot}hr/ml$. $C_{max}$ values of SRP and PZQ were $90.7{pm}82.2ng/ml;and;214.9{pm}251.9;ng/ml$, and $T_{max}$ values were $3.42{pm}1.43;hr;and;1.96{pm}1.23;hr$, respectively. SRP tablets showed similar AUC values, but lower $C_{max}$ and longer $T_{max}$ values than PZQ. In the phase 2 study, SRP at 30 mg/kg (single dose) achieved a 60% cure rate and a 95.5% egg reduction rate. The cure rate of a single dose SRP was unsatisfactory compared with that of the conventional PZQ dose, but much better than that achieved by a single dose PZQ.