Research the influence of coconut fiber addition to the manufacture of concrete knock down as building materials. The purpose of this study to determine the effect of coconut fiber addition to the making of knock down concrete. This research uses experimental design of knock down in the form of Figures and Graphs and the collection is analyzed descriptively with the addition of coconut fiber treatment consisting of: 50; 100; 150; 200; 250 and 300 g, the properties and advantages of coconut fiber are: resistant to water, microorganisms, weathering and also to mechanical workmanship that is friction and punch. Each treatment was repeated 3 (three) times. The results showed that the addition of coconut fiber was the very significant effect on water absorption and compressive strength. The results showed that the average water absorption was 4.51 - 8.25% and the average compressive strength was 173,49 - 209,34 kg / cm2. For the compressive strength direction, treatment D is the optimal addition of coconut fiber because it provides the highest compressive strength value of 209.34 kg / cm2, while the E and F treatment of the compressive strength decreases. The results showed that the best treatment was obtained in treatment A; B; C; D and E can meet the quality requirement of knock down concrete because the compressive strength can reach 175 kg / cm2 and can be used for wall concrete. Keywords : knock down, coir, compressive strength, absorptionABSTRAK Penelitian pengaruh penambahan serat sabut kelapa terhadap pembuatan beton knock down sebagai bahan bangunan. Tujuan penelitian ini untuk mengetahui pengaruh penambahan serat sabut kelapa terhadap pembuatan beton knock down. Penelitian ini menggunakan desain percobaan pembuatan knock down dalam bentuk gambar dan grafik serta data dianalisis secara deskriptif dengan perlakuan penambahan serat sabut kelapa yang terdiri dari: 50; 100; 150; 200; 250 dan 300 g, sifat dan keunggulan dari serat sabut kelapa yaitu: tahan terhadap air, mikroorganisme, pelapukan dan juga terhadap pengerjaan mekanis yaitu gesekan dan pukulan. Masing–masing perlakuan diulang 3 (tiga) kali. Hasil analisis menunjukkan bahwa perlakuan penambahan serat sabut kelapa memberikan pengaruh sangat nyata terhadap penyerapan air dan kuat tekan. Hasil penelitian menunjukkan bahwa hasil penyerapan air rata-rata 4,51 - 8,25 % dan kuat tekan rata-rata 173,49 - 209,34 kg/cm2. Untuk parameter kuat tekan, perlakuan D merupakan penambahan serat sabut kelapa yang optimum karena memberikan nilai kuat tekan tertinggi yaitu 209,34 kg/cm2, sedangkan perlakuan E dan F nilai kuat tekannya semakin menurun. Hasil menunjukkan bahwa perlakuan yang terbaik diperoleh pada perlakuan A; B; C; D dan E dapat memenuhi syarat mutu beton knok down karena kuat tekannya dapat mencapai 175 kg/cm2 dan dapat dimanfaatkan untuk beton dinding.Kata kunci: knock down, serat sabut kelapa, kekuatan tekan, penyerapan