Variety field trial is costly because many traits are observed over a lot of locations. Take two Official Maize Field Trials of china as an example, northeast and north china planting spring corn (NNCSC for short) covers about 23 locations, and huang-huai-hai plain planting summer corn (HHHSC for short) have about 29 tests a year. For each variety in any location, about 30 traits are observed. But in our study, we found that various traits need different amounts of tests, some traits are easy to gain reliable observables, and some difficult. So, each location can also differ in function positioning and traits observing to improve resource allocation of variety field trial. For traits need less amounts of tests or less important, we suggest observe these traits only in several core location; for traits need more tests or important, we suggest observe these traits in all tests.