This research aims to study the application of kaolin with coconut fiber corncobs fiber and durian peel in concrete masonry unit wall for increasing effective heat protection and lightweight. The ratio of cement type 1: kaolin is equal to 1: 60 by weight. The kaolin is replaced by fiber include coconut fiber corncob fiber durian peel fiber with 1.67% 3.33% and 5% by weight of kaolin. The kaolin concrete block mixed with fiber sample size is formed to 6.9 x 39 x 19 centimeter with the hydraulic compactor. The samples tested in physical and mechanical properties follow the TIS 58-2533 standard. Resulting their fibers can reduce the density thermal conductivity and compressive strength and increase the changing length and water absorption of kaolin concrete blocks. The kaolin concrete block without fiber has highest compressive strength followed by the kaolin concrete block mixed with corn cob fiber the kaolin concrete block mixed with coconut meal fiber and the kaolin concrete block mixed with durian peel fiber has lowest compressive strength respectively. However their fibers have possibility to be composite materials to reduce weight of kaolin concrete blocks