Plastics are broadly grouped into thermosetting plastics and thermoplastics, and thermoplastics are further grouped based on properties such as heat resistance and mechanical strength. Apart from these mechanical and thermal properties are the optical properties of plastics that include transmittance, reflectance, and haze. Haze refers to the proportion of diffuse transmittance to total transmittance, and is used to evaluate material surface treatment (roughness and matte). Materials used for solar cells may also have aperiodic structure (textured structure) on their surface to increase dispersion and contain light. Measuring the haze of plastic materials is defined by international standard ISO 14782, while the same content is reproduced in Japanese Industrial Standard (JIS) K 7136.1), 2) This article describes analyzing plastics of different properties using Shimadzu UV-3600 Plus UVVIS-NIR spectrophotometer with ISR-1503 integrating sphere attachment to calculate their haze and solar transmittance.