Blood　distribution　and　plasma　protein　binding　are　the　important　properties　that　can　influence　pharmacokinetics　and　ultimately　the　anticancer　efficacy　of　photosensitizers　in　clinical　photodynamic　therapy.　As　a　novel　and　promising　phthalocyanine　photosensitizer　under　clinical　phase　II　investigation　in　China,　the　superiority　of　PHOCYANINE　is　speculated　on　its　attribution　to　its　binding　with　plasma　proteins.　To　verify　this　hypothesis,　explore　the　targeting　mechanism　and　further　apply　foundation　for　its　clinical　trial　evaluation,　we　further　study　its　in　vitro　and　in　vivo　human　blood　distribution,　in　vitro　plasma　protein　and　lipoprotein　binding　in　detail.　PHOTOCYANINE　was　found　to　be　mainly　distributed　in　plasma　with　low　K　BP　and　K　EP　values.　Moreover,　its　high　binding　rates　to　plasma　proteins　among　various　species　(mouse,　rat,　dog,　monkey,　and　human)　were　then　determined.　Among　these　plasma　proteins,　human　serum　albumin　and　al-acid-glycoprotein　were　found　to　bind　PHOTOCYANINE　highly,　and　low-density　lipoproteins　have　the　highest　percentage　of　PHOTOCYANINE　over　other　lipoproteins.　This　study　is　expected　to　provide　some　guidance　for　PDT　clinical　evaluations　and　for　further　molecular　design　and　development　of　photosensitizers.