Three flavanonol namely quercetin, dihydroquercetin and dihydromyricetin were isolated from ethyl acetate fraction of Picea smithiana (wall) Boiss by using standard isolation schemes. The isolated flavanonol were evaluated for their enzyme inhibition potential against urease, carbonic anhydrase and Phosphodiesterases-I. Flavanonol showed significant activity against urease with IC50 value of 29.73 ± 1.22 μM, While quercetin and dihydroquercetin were found to be weak inhibitors of urease with IC50 values of 208.87 ± 2.11 and 202.87 ± 2.01 μM respectively. Thiourea was used as a standard for the inhibition of urease enzyme (IC50=21 ± 0.12). On the other hand flavanonol 2 showed potent activity against phosphodieseterase-1 when compared with the standard EDTA (IC50=273 ± 1.69 μM). Newly identified inhibitors of enzyme may lead for the discovery of new drug to treat urolithiasis, and cardiovascular associated disorder. In silico drug designing plays an important role in the discovery of new inhibitors against the target. Compounds 1-3 were screen for docking study. The docked conformations of compounds 1-3 and reference thiourea showed potency of compounds 1-3. From the docking statistics, it is observed that the binding affinity of compound 3 is -8.5 kcal/mol (Autodock vina docking energies), which is best than the standard thiourea (-3.4 kcal/mol).