The purpose of this study was to find out the position of the emergence of flowers associated with the formation of fruit-set as a potential fruit on the citrus Siam plant. This study used a randomized block design with two factors observed that is flower position on the branch and flowering period. The results of the statistic data tabulation show that. The interaction between the positions of the flowering period on citrus Siam plants is not significantly different. The position of the emergence of the flower determines many fruit-set are formed. Top branch. The position of the top branch shows the percentage of fruit-set is formed more that is 97,95 % and the lowest in rootstock, that is 91,30. This incident was supported by more interest formed when the top branch that’s is 224,95 florets more 53,65 % if it is stretched in the lower stem position 104,27 florets. This is supported by relative water content, chlorophyll, N, P, K and sucrose leaves i.e. 46,78 %, 28,82 %, 1,40 %, 0,74 %, 3,42 % and 3,42 % bigger than the lower stem i.e. 41,36 %, 18,64 %, 1,16 %, 0,19 %, and 2,17 %.