ABSTRACT: Orange fruits were collected from one of the gardens of Baqubah / Diyala / Iraq in January of 2020, while samples of leaves and flowers were collected in March of the same year, for the purpose of completing the research procedures. The present study aims to estimation of phenolic compounds and evaluation of their antioxidant activity of the extract of some parts of the orange plant. The results show a variation in the parts of the orange plant in their content of phenolic compounds. Moreover, the statistical analysis pointed to the presence of significant differences at the probability level of P <0.05 among the parts of the orange plant, in Total Phenolic Content (TPC) and Total Flavonoid Content (TFC). The leaves are superior in their (TPC) which record the highest in comparison with the juice, which recorded the -1 concentration of 145.71 mg( GAE) .g . Though the highest (TFC) in the mesocarp of fruit is -1 lowest (TPC) 57.18 mg( GAE) .g in the juice, which gave the -1 compared to 5.81 mg.Querecetin. g mg Querecetin .g-1 11.14 lowest (TFC). On the other hand, the result of statistical analysis showed significant difference among the parts of orange plant at the probability of P <0.05 in antioxidant activity. The result showed that the highest antioxidant activity, detected by using the DPPH scavenging . While the lowest value of the free radicals DPPH -1 test of the flowers is 2.64 mg. mL was obtained from exocarp. The statistical analysis -1 inhibition, which was 0.86 mg. mL results indicated a positive correlation among the (TPC), (TFC) and the antioxidant activity of DPPH free radical test with value of 0.385 and 0.484 respectively.