To enhance the reliability of essay assessment, the application of assessment standards and teaching method of rewriting are suggested in this paper. To establish assessment standards, the level of students' essay writing ability has been analyzed in the categories of knowledge, expressiveness and thinking ability. The ‘knowledge’ can be evaluated at the aspects of ‘argument’, ‘correctness of knowledge’ and ‘coherence’. The ‘expressiveness’ is based on ‘vocabulary’, ‘sentence’ and ‘organization’. Finally, the ‘thinking ability’ can be divided into the categories of ‘creation of ideas’, ‘logicality’, ‘persuasiveness’ and ‘originality’. The method of essay assessment are structuralized on the basis of assessment elements. Assessment advice is corrective feedback that must be followed after essay test through which the most crucial weakness of testee is determined. The advice after grasping the learner's ability thoroughly can lead to easy rewriting and foster positive attitude of essay writing.