A piezo-pneumatic valve driving type dispensing pump having an improved dispensing speed and a simplified structure, and a method of dispensing a viscous liquid by using the pump. Accordingly, a viscous liquid may be easily dispensed by reciprocating a valve rod inserted into a reservoir storing the viscous liquid, by using an air pressure. In particular, the air pressure may be precisely controlled by opening or closing a flow passage allowing the air to enter or exit, by using a piezoelectric element-based piezoelectric valve. Thus, the valve rod may be operated precisely at a high speed so that an exact amount of the viscous liquid is dispensed at a high speed.