**Exhibit 31.2**

 

**CERTIFICATIONPURSUANT TO**

**18 U.S.C.RULE 13a-14(a)/15d-14(a)**

**ASADOPTED PURSUANT TO**

**SECTION 302OF THE SARBANES-OXLEY ACT OF 2002**

 

I, Wilson W. Cheung,certify that:

 

1.            I have reviewed this quarterlyreport on Form 10-Q/A of AXT, Inc.;

 

2.            Based on my knowledge, this reportdoes not contain any untrue statement of a material fact or omit to state amaterial fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading with respectto the period covered by this report;

 

4.            The registrant’s other certifying officer(s) andI are responsible for establishing and maintaining disclosure controls andprocedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e))and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and15d-15(f)) for the registrant and have:

 

(a)           Designedsuch disclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure that materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared;

 

(b) Designedsuch internal control over financial reporting, or caused such internal controlover financial reporting to be designed under our supervision, to providereasonable assurance regarding the reliability of financial reporting and thepreparation of financial statements for external purposes in accordance withgenerally accepted accounting principles;

 

(c) Evaluatedthe effectiveness of the registrant’s disclosure controls and procedures andpresented in this report our conclusions about the effectiveness of the disclosurecontrols and procedures, as of the end of the period covered by this reportbased on such evaluation; and

 

(d) Disclosedin this report any change in the registrant’s internal control over financialreporting that occurred during the registrant’s most recent fiscal quarter (theregistrant’s fourth fiscal quarter in the case of an annual report) that hasmaterially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and

 

5.            The registrant’s other certifyingofficer and I have disclosed, based on our most recent evaluation of internalcontrol over financial reporting, to the registrant’s auditors and the auditcommittee of the registrant’s board of directors (or persons performing theequivalent functions):

 

(a) Allsignificant deficiencies and material weaknesses in the design or operation ofinternal control over financial reporting which are reasonably likely toadversely affect the registrant’s ability to record, process, summarize and reportfinancial information; and

 

(b) Anyfraud, whether or not material, that involves management or other employees whohave a significant role in the registrant’s internal control over financialreporting.

 
| /s/  WILSON W. CHEUNG    |   |
|--------------------------|--------|
| Wilson W. Cheung         |
| Chief Financial  Officer |
| May 21, 2008        |

 

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