Abstract: A device for measuring bidirectional reflectance and transmittance distribution of a leaf in the plane of incidence was designed with a micro-powered laser diode for illuminating and a silicon photocell detector rotating around sample for recording scattering light intensity from the sample. Illuminating by light source with wavelength of 650 nm and 830 nm, bidirectional reflectance from a white board (taken as reference) and bidirectional scattering (in reflectance and transmittance) from a leaf of evergreen euonymus (Euonymus japonicus Thumb.) in the plane of incidence were measured separately. The results showed that the device gave good measurement reproducibility. This device can be used in the research of radiant transfer of plant canopy.