some 1 send me mail from outlook 2003 as html format in my Thunderbird,but i can't see it in original format,its seems huge line spacing & wrap text doesn't show.how can i see this mail in original format?

You probably are seeing it in its original format.

I use the settings in Thunderbird (and Firefox) to set content to how I want to see it, not as the sender wished. After all, it's the requirements of MY eyesight that need to be satisfied, not theirs.

Tools|Options|Display|Formatting→Advanced

Select the appropriate region at the top (Western and Unicode will be usually be important to most English speakers) and set what fonts you like, and their sizes. Setting a minimum font size is useful, and I prefer to not allow messages/pages to choose their own fonts.

When you have finished, make sure the default font shown at

Tools|Options|Display|Formatting→Default font:

…is correct. If the last fonts page you looked at used an infrequently used font, it may have "stuck" as the default.

More here: http://www.ramsden.org.uk/9_Type_sizes.html

A quick and temporary fix might be to view it as plain text:

View|Message Body As|Plain Text

As a compromise between "Original" and "Plain Text" you can try "Simple HTML" which removes some but not all formatting. Microsoft Office uses quite a few proprietary styles and non-standard HTML encoding, thus may confuse other e-mail clients. The same applies to plain-text messages where they came up with their own encoding for "soft" line breaks rather than using published standards.