The cloud storage has been increasingly used for convenient data sharing, integration, and transactions among multi-owner groups to promote considerable profits, where the ownership of outsourced data is guaranteed by various provable data possession (PDP) schemes. Existing works mainly focus on ownership confirmation, while overlooking evaluation of distinct data contributions from different group members, which, however, will cause unfair distribution and further commercial dispute. In this paper, by considering strong privacy-preserving demand in public group transactions, we propose TA-PDC, the first Provable Data Contribution with Traceable Anonymous, to resolve absence of evaluation towards data contribution within a multi-owner group. Our key insights are following twofold: 1) designing a novel weighted tag structure based on linkable ring signatures to correctly linking tags with weight embedded to specific owner; 2) using succinct inner product arguments (IPA) to enable a public verifiable commitment about data contribution without disclosing the underlying details. Our TA-PDC supports batch verification to further enhance efficiency and fine-grained contribution querying for greater flexibility. Security analysis and evaluations justify security and practicality of our proposal.