The Yokine resident received a certificate in recognition of her achievement and has vowed to knit another 500 jumpers.
�I�ll just keep going until I can�t do anymore,� she said.
�It is relaxing, but also I know at the end that it�s going to keep a child warm.�
Ms Thomson donates the jumpers and knitted accessories to the CWA, which distributes them to children in need.
She learnt to knit from her grandmother and often knits cardigans for herself and her family.
�It makes me feel good knowing that someone is going to be kept by warm by what I�ve knitted,� she said.
�When I finish a garment and fold it, it�s folded with love.
�I think they are warmer when you knit them yourself.�
Ms Thomson said she was �over the moon� when she received the certificate from CWA in recognition of three years worth of knitting.