The spray characteristics of gasoline, n-butanol and ethanol injected from an outward-opening gasoline piezoelectric injector were investigated with Schlieren and laser Mie scattering techniques in a constant volume vessel. Experimental results showed that the hollow conical spray was composed of numerous tiny jets. The macrostructures of spray were affected by the magnitude of back pressure. With the increase of back pressure, the gap between two adjacent jets was decreased and finally disappeared. In the meantime, the penetration and projected area of spray were sharply reduced. However, the spray cone angel was nearly unchanged with time regardless of the magnitude of back pressure and fuel types. Furthermore, the decline of spray penetration was always larger in horizontal direction than that in vertical direction. But the penetration in horizontal direction was longer than that in vertical direction. The spray penetration in vertical direction for ethanol and n-butanol with relatively higher viscosity was longer than that for gasoline, which was contributed to the vortex formed during injection. The larger the scale of the vortex, the longer the penetration in horizontal direction was.