We have studied hadronic events from e+e– annihilation data at centre-of-mass energies from 60 to 197 GeV.The operation of the AMY and OPAL collaborations at many different collision energies offers a unique opportunity to test QCD by measuring the energy dependence of different observables. The main results concern the measurement of the strong coupling constant, αs , from hadronic event shapes . The coupling constant, αs, is measured by two different methods, first by employing the three jet observables. Combining all data, the value of αs at Next-to-Next leading order( NNLO) is determined to be 0.117± 0.004(hard) ± 0.006(theo). Next, from the event shape distributions, we extract the strong coupling constant, αs, at NNLO and test it\\\\\\\'s evaluation with energy scale. The results are consistent with the running of αs, expected from QCD predictions. Averaging over different observables, the value of αs is determined to be 0.115± 0.007(hard) ± 0.003(theo).

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