Experimental investigation results of the fuel injector group in a heavy-duty gas turbine are presented. Atomization characteristic has great impact about combustion, inflame, temperature field of outlet. Obtained atomization characteristic about spray particle size and spray angle using LDV/PDPA system, determined dimension of injector group. On the basis of these tests, the combustion testing of the injector group in the flame tube is made, its every targets are arrived in the design requirements. This has demonstrated: the test systems and test methods are practical, feasible and reliable. These experimental data have provided the reliable basis for the injector group design and development.