Spin-trimer chain systems are of current interest due to unconventional properties arising from the strong quantum fluctuations and topology, such as, quantum phenomenon of magnetization plateau. The presence or absence of plateaus is strongly related to the relative strength and sign of the intratrimer and intertrimer exchange interactions. Therefore, determination of the sign and strength of the exchange interactions is essential to shed light on quantum magnetization plateau. We propose inelastic neutron scattering studies on spin-1/2 trimer chain compound Na2Cu3Ge4O12 using the MERLIN spectrometer to determine the spin Hamiltonian. The present experimental study will shed light on the unconventional magnetic properties of the spin trimer chains such as quantum phenomenon of magnetization plateau. Experimental results will be useful to develop theoretical models in such systems.