In Australian schools, there are two main terms of assessments--assessment for educational accountability and assessment for learning. The assessment for accountability mainly refers to the standardised test which concerns students academic performance rather than students' learning. As a main term of assessment in Australia, standardised testing has some disadvantages which will be less beneficial for teachers' teaching and then lead to low academic achievement of students. Besides that, the teacher is a crucial part to enact the policy to improve students' learning. Also, the complex situation of Australian secondary schools will influence the policy enactment. Therefore, it is significant to have a better understanding of the limitations of the standardised testing on teachers to improve students' learning not only in academic area but in other important areas. The author will argue that the negative impacts of standardised assessments on teachers in Australian secondary schools outweigh the positive impacts. In order to support the argument, the author will take NAPLAN as an example to first analyse the negative effects of standardised assessments on teachers and then explore the negative impacts on teaching practice before making a conclusion and presenting some recommendations in the final part.