no particular affect to PR application
By contract means the company needs to re-offer you after the contract expire. It has no particular affect to your PR application, unless it is too shorter (saying less than 1 year).

合约形式
大公司或一年以上的合约，应该对申请PR没有影响

谢谢，还有疑问：除了by contract, 还有其他的什么类型么？
有什么区别吗？

temp/contract/permanent
If you are under contract, the employer can opt not to renew the contract without giving any reasons when the old one expires, which means you lose the job without any compensation.

If you are under permanent employment, the employer can still fire you but probably need an excuse and you will be somewhat comepensated for it.

There are other benefits that only applicable to Perm staff like extra medical/insurance coverage, long sevrvice award etc.